Impact of sourdough on the texture of bread

Sourdough has been used since ancient times and its ability to improve the quality and increase the shelf-life of bread has been widely described. During sourdough fermentation, lactic acid bacteria (LAB) produce a number of metabolites which have been shown to have a positive effect on the texture and staling of bread, e.g. organic acids, exopolysaccharides (EPS) and/or enzymes. EPS produced by LAB have the potential to replace more expensive hydrocolloids used as bread improvers. Organic acids affect the protein and starch fractions of flour. Additionally, the drop in pH associated with acid production causes an increase in the proteases and amylases activity of the flour, thus leading to a reduction in staling. While improving the textural qualities of bread, sourdough fermentation also results in increased mineral bioavailability and reduced phytate content. In this review we will be discussing the effect of sourdough on wheat and rye bread as well as the potential of sourdough to improve the quality of gluten-free bread.     

Growth inhibition of Fusarium graminearum and deoxynivalenol detoxification by lactic acid bacteria and their application in sourdough bread

Eight lactic acid bacteria (LAB) strains were screened for their ability to inhibit Fusarium graminearum (F. graminearum) growth and remove deoxynivalenol (DON). Furthermore, the selected LAB strains were applied as starter cultures to evaluate their performance during the breadmaking process. Lactobacillus plantarum (L. plantarum) AR524 exhibited strong inhibitory activity against F. graminearum growth in a pH-dependent manner and removed up to 40.9% of DON, mainly through cell wall binding. Compared with the control, L. plantarum AR524 inhibited 60.19% of F. graminearum growth and removed 50.53% of DON during breadmaking. The texture properties of the bread were also remarkably improved by L. plantarum AR524, and its shelf life was extended from 3 days to 6 days without the application of any chemical preservatives. Therefore, L. plantarum AR524 shows excellent potential for application as a bioprotective starter culture in bakery products.     

乳酸菌胞外多糖发酵条件优化及对馒头品质的影响

从老面中分离出一株高产胞外多糖的乳酸菌L1,经鉴定为植物乳杆菌,研究结果表明:L1菌株在C∶N为2∶1、培养基的初始pH为6左右、培养温度为30℃、培养时间为18 h的条件下,产糖量最高,添加乳酸菌L1胞外多糖的馒头比容明显增大,白度略微增大,感官评分较高。     

Comparison of the effect of exopolysaccharide-producing lactic acid bacteria from sourdough on dough characteristics and steamed bread quality

The use of exopolysaccharide (EPS)-producing lactic acid bacteria (LAB) is promising in sourdough fermentation. However, the knowledge of the effects of various species of LAB on steamed bread making remains limited. In this study, the effects of two LAB with high EPS-producing capacity, namely Weissella cibaria L32 and Lactobacillus brevis L17 on dough fermentation and steamed bread quality were estimated. The addition of these two LAB strains significantly increased the titratable acidity and protease activity during the dough fermentation, especially L. brevis L17. Although the in situ EPS synthesised by LAB could improve the steamed bread quality, excessive acidification of L. brevis L17 would still increase the protease activity and thus destroy its gluten network structure. As a result, the steamed bread fermented with L. brevis L17 had the lowest specific volume and hardest texture in comparison with the steamed bread fermented with W. cibaria L32 and with added EPS produced by W. cibaria L32 and L. brevis L17. These results indicated that different EPS-producing LAB exhibited distinctive dough fermentation characteristics, and the in situ EPS-producing W. cibaria L32 could improve steamed bread quality, which confirmed its potential application in steamed bread making.     

Effects of a bacteriocin-like substance produced by Leuconostoc mesenteroides subsp. cremoris on spoilage strain Lactobacillus fructivorans and various pathogens

Certain lactic acid bacteria present in the natural flora of the wine fermentation medium perform the malolactic fermentation process and other biochemical activities which lead to the formation of the outstanding aroma and bouquet of wine. However, because of the spoilage phenomena caused also by certain lactic cultures, off‐odours formed via metabolic side reactions cause severe economic losses in the wine industry. Several control mechanisms were introduced in order to eliminate these spoilage cultures, but none of these has been implemented as an efficient and healthy process. A partially purified bacteriocin‐like inhibitory substance (BLIS) with a molecular weight of 32 000 Da, obtained from a Leuconostoc mesenteroides subsp. cremoris isolate belonging to the native flora of wines of the Cappadocia region, was studied for its inhibitory activity on the spoilage strain, Lactobacillus fructivorans, isolated from the same wine flora and several other pathogens, and was found to be efficient in eliminating both the spoilage strain and the pathogens.     

不同乳酸菌发酵酸面团对面包品质及风味的影响

以酸面团典型菌株植物乳杆菌(Lactobacillus plantarum,Lp)、类食品乳杆菌(Lactobacillus paralimentarius,Lpa)和发酵乳杆菌(Lactobacillus fermentum,Lf)为发酵菌,探讨自然发酵酸面团(对照),3种单一乳酸菌和4种复合乳酸菌Lpa+Lp (1...